Rethinking domain-general and domain-specific reasoning processes

This dissertation comprises three papers. Paper 1 examines performance on conjunctive reasoning problems. Conjunctive judgments on three kinds of tasks are investigated. The results suggest that subjects' probability estimates reflect the operation of task-specific rules for combining probabilities. Paper 2 examines the effects of expectations on conditional reasoning using the Wason card selection task (Wason, 1966). The results suggest that if subjects are led to expect violations of a conditional rule, they are more likely to falsify that rule than when they are led to believe that violations are unlikely. However, expectations only affected performance on aschematic rules, not on schematic (social contract) rules. Paper 3 examines the effects of some general constraints on reasoning that derive from the properties of schemata. The results suggest that facilitation on the selection task can be obtained with any content, as long as that content can be made to conform to these constraints. The results also suggest that working memory capacity plays a role in selection task performance.